Evaluation of medical X-ray machines in Paraíba state radiology centers between 2008 and 2009 *

Transcrição

1 Evaluatio ORIGINAL of medical ARTICLE X-ray machies i Paraíba state radiology ceters betwee 2008 ad 2009 * Avaliação das codições de fucioameto dos equipametos de raios X médico em serviços de radiologia o Estado da Paraíba, durate os aos de 2008 e 2009 Adriaa Carla Rodrigues Medes 1, Christiae Lucea Ramos 2, Dailo Waderley Matos de Abreu 3 Abstract Resumo Objective: To evaluate the light ad radiatio fields cogruece ad radiatio beam aligmet i medical X-ray equipmet i Paraíba state radiology ceters by meas of two quality cotrol tests. Materials ad Methods: A loaded cassette, a measurig tape ad a bubble level were utilized i the field size ad aligmet testig. The evaluatio of collimatio systems accuracy ad X-ray beam aligmet was udertake durig health ispectios performed i radiology ceters betwee 2008 ad Results: I 2008, 121 X-ray machies were evaluated i the Paraíba state. I 2009, 117 machies were tested. From this uiverse, machies were selected for compariso, sice they were evaluated both i 2008 ad 2009, with ( = 16) showig test results improvemet from oe year to aother. Coclusio: The percetage of problematic X-ray machies decreased betwee 2008 ad 2009, otwithstadig o quality assurace program has bee observed i Paraíba state radiology ceters. Keywords: Equipmet; X-rays; Quality cotrol. Objetivo: Avaliar a coicidêcia etre o campo lumioso e o campo de radiação, e o alihameto do feixe de radiação dos equipametos de raios X médico o Estado da Paraíba, por meio de dois testes de cotrole de qualidade. Materiais e Métodos: Foram utilizados os dispositivos para os testes de tamaho de campo e de alihameto, um chassi carregado, trea e ível de bolha. Os testes de exatidão do sistema de colimação e de alihameto do raio cetral do feixe de raios X foram realizados durate as ispeções saitárias em serviços de radiologia os aos de 2008 e Resultados: No ao de 2008, 121 equipametos de raios X foram testados o Estado da Paraíba. No ao de 2009, passaram pelos testes 117 equipametos. Deste uiverso, foram selecioados para a comparação por terem sido avaliados tato o ao de 2008 como em 2009, sedo observada uma melhoria de 18,60 ( = 16) os resultados dos testes realizados de um ao para outro. Coclusão: Pode-se cocluir que o percetual de equipametos apresetado problemas o seu desempeho sofreu uma dimiuição etre 2008 e 2009, ão sedo observado programa de garatia de qualidade em ehum dos serviços de radiologia do Estado da Paraíba. Uitermos: Equipameto; Raios X; Cotrole de qualidade. Medes ACR, Ramos CL, Abreu DWM. radiology ceters betwee 2008 ad INTRODUCTION I medicie, radiological images are utilized as a aid to diagosis, treatmets ad also i images-guided procedures. For such purposes, the image must meet a certai * Study developed at Agêcia Estadual de Vigilâcia Saitária da Paraíba (Agevisa-PB), João Pessoa, PB, Brazil. 1. Master of Prevetive ad Child Detistry, Health Surveyor, Agêcia Estadual de Vigilâcia Saitária da Paraíba (Agevisa-PB), João Pessoa, PB, Brazil. 2. Specialist i Pediatric Detistry, Health Surveyor, Agêcia Estadual de Vigilâcia Saitária da Paraíba (Agevisa-PB), João Pessoa, PB, Brazil. 3. Master of Urba Egieerig, Health Surveyor, Agêcia Estadual de Vigilâcia Saitária da Paraíba (Agevisa-PB), João Pessoa, PB, Brazil. Mailig Address: Adriaa Carla Rodrigues Medes. Rua Lidolfo José Correia das Neves, 419, ap. 502, Jardim Oceaia. João Pessoa, PB, Brazil, medesadriaa1@ hotmail.com level of quality, so as to miimize errors of iterpretatio ad idetificatio of structures, thus allowig a accurate diagosis with low radiatio levels. Otherwise a low quality image causes the repetitio of imagig studies ad, cosequetly, the duplicatio of radiatio dose i the same patiet, besides additioal costs to the radiology service (1). The beefits from a appropriate radiological image ca be attaied by meas of the implemetatio of equipmet quality assurace programs i radiodiagosis ceters. Accordig to the World Health Orgaizatio, quality assurace i diagostic Received October 20, Accepted after revisio Jue 29, radiology is defied as a orgaized effort by the service maagemet towards assurig that images are acquired with eough quality to allow a appropriate diagosis with the lowest radiatio dose to the patiet (2). I Brazil, the developmet of techiques ad devices for quality cotrol i radiology started at the Physics Departmet i the Ribeirão Preto Campus of Uiversidade de São Paulo sice the mid-1970s, by Professor Thomaz Guilardi Neto, assisted by Professor Joh Camero. Professioals were educated ad prepared to perform evaluatio techiques, ad have implemeted the first quality programs of throughout São Paulo ad other Brazilia states Colégio Brasileiro de Radiologia e Diagóstico por Imagem

2 With the publicatio of Resolutio SS 625/94, of December 14, 1994, the implemetatio of quality cotrol programs became madatory i the state of São Paulo (3). Followig the successful implemetatio of the programs i the state of São Paulo, the Miistry of Health issued the Order (Portaria) MS/SVS 453, o Jue 1st, 1998 (1). Order 453 establishes the eed to implemet a quality assurace program (QAP) i radiology ceter (4,5). As a result, it establishes that every diagostic X-ray equipmet must be subject to periodical evaluatio of their performace by meas of several costacy tests, such as, for example: measuremet of the represetative dose value delivered to the patiets submitted to radiography at the ceter; testig of the accuracy of X-ray tubes voltage idicator (kvp); evaluatio of the accuracy of exposure time, as applicable; testig of the X- ray beam aligmet; X-ray tube performace test; testig of the air kerma rate liearity as a fuctio of the mas, testig of automated exposure system reproducibility; measuremet of the focal poit size; evaluatio of collimatio system accuracy; ad grid aligmet test (6). For the preset study, Agêcia Estadual de Vigilâcia Saitária da Paraíba (Agevisa- PB) (Paraíba State Departmet of Health Surveillace) provided the research istrumets required for the testig of collimatio system accuracy ad X-ray beam aligmet. Because of their simplicity ad facility, the tests allowed a critical evaluatio of the apparatuses with respect to collimatio of radiatio i the patiets areas of iterest ad the distortio of the radiographic image, allowig the miimizatio of risks resultig from radiatio exposure, miimizatio of the dose delivered both to patiets ad workers, costs optimizatio, reductio of films rejectio ad wear o the equipmet, besides a better quality i radiographic image stadards, thus cotributig for accurate diagoses (7). The collimatio system accuracy testig is aimed at evaluatig the cogruece betwee the light ad radiatio fields limited by the equipmet collimator, thus avoidig X-rays reachig uiteded areas of the patiet s body durig the radiological examiatio. O the other had, the testig of X-ray beam aligmet is aimed at evaluatig the perpedicularity betwee the ceter of the light field ad the plae of the image receptio system, thus avoidig the radiographic image distortio (8). The preset study was aimed at evaluatig the light ad radiatio fields cogruece ad radiatio beam aligmet i medical X-ray equipmet i Paraíba state, private ad philathropic radiology ceters by meas of two quality cotrol tests (QCT) as follows: testig of collimatio system accuracy ad X-ray beam aligmet performed i the years of 2008 ad 2009 by the techical team of the Agevisa-PB ioizig radiatios sector. MATERIALS AND METHODS The preset study is of the observatioal, descriptive ad comparative type, as it iforms, i quatitative terms, o the distributio of a evet i the populatio, ad compares the testig results i the same apparatuses i differet years (9). The data recordig was performed by a sigle ivestigator ad the visits were carried out durig health surveillace ispectios followig the ormal operatioal routie of the radiological ceters. Because of ethical cofidetiality cosideratios, the hospitals ad radiological ceters visited durig the preset study were ot idetified. So, ispected istitutios are oly classified accordig to the service etwork they belog to, as public, private ad philathropic. I 2008, 121 X-ray apparatuses belogig to 87 radiology services i the state of Paraiba uderwet QCT. Amog them, ( = 51) beloged to the public health system, ( = 67), to private cliics, ad 2.47 ( = 3), to philathropic ceters. I 2009, 117 apparatuses were submitted to the same tests i the Paraíba state, ( = 45) of them i the public health etwork, ( = 66), i the private etwork, ad 5.12 ( = 6) i the philathropic etwork. Of this uiverse, ( = ) of the apparatuses were selected for compariso, sice they had bee evaluated both i the years of 2008 ad The tests performed i the preset study were the followig: X-ray beam aligmet collimatio system accuracy, accordig to the Brazilia protocols for QCTs (6,10) ad a medical radiodiagosis hadbook (11). The followig istrumets were utilized for each evaluatio: devices for field size testig (plate with radiopaque markigs with two orthogoal axes i scales of 0.5 cm ad two cocetric circles) ad, for the X-ray beam aligmet (a plastic cylider with 0.8 mm-diameter steel spheres placed at lower ad upper bases at a distace of 15 cm), a (preferably 24 30) cassette loaded with film, a measurig tape ad a bubble level (8,12). For the evaluatio of the collimatio system accuracy, a loaded cassette was placed o the table s surface, ad over such cassette the device for field size measuremet, i such a way that such device was perpedicular to the X-ray beam. After adjustmet of the focus-film distace to 1m, the adjustmet of the edges of the light field was made so that it matched the rectagular outlie of the plate, through the X- ray equipmet collimator. For the X-ray beam aligmet, the beam aligmet device was placed at the ceter of the collimator test device. Subsequetly, a exposure utilizig approximately 40 kvp ad 3 mas (11) was made. After the evaluatio of the tests results, i those cases i which the X-ray apparatuses were ot i compliace with the stadards, the istitutios to which they beloged were otified ad deadlies were established for corrective maiteace, after which the ispectio team would perform ew tests i the same apparatuses to check o the adjustmets made. I the preset study, i order to evaluate the results, the X-ray apparatuses were classified accordig to their models, ito fixed equipmet ad portable equipmet. The portable apparatuses that were beig utilized as fixed equipmet were icluded i the preset study as fixed equipmet. RESULTS The data obtaied by the preset study developed i the years of 2008 ad 2009 are categorical, with o margi for error. Amog the apparatuses existig i the Paraíba state, a sigificat sample (71.07; = ) was aalyzed i both years. 245

3 The cogruece betwee the light ad radiatio fields was evaluated for aalysis ad iterpretatio of the images of the collimator test. The largest distace betwee the borders of the light field ad those of the radiatio field was measured. The greater the cogruece betwee the light ad the radiatio fields, the better is the aligmet. The differece betwee the borders of the radiatio field ad the borders of the light field must ot be greater tha 2 of the focus-film distace that is ±2 cm away from the lie correspodig to the device s rectagle (9,11). The images geerated o this test are represeted o Figures 1 ad 2. As regards the aalysis ad iterpretatio of the X-ray beam aligmet test, the locatio of the image of the sphere o the top of the cylider was verified. If the image of the upper sphere was withi the first circle, the icliatio correspoded to < 1.5. I those cases where the image of the upper sphere was located betwee the first ad the secod circles, the icliatio was < 3 (11). Wheever the image of the upper sphere itercepted the secod circle, the perpedicularity of the cetral ray must be corrected (8). Figures 3 ad 4 represet the images of the X-ray beam cetral axis aligmet test. I the preset study, i the year of 2008, QCTs were performed i 92 fixed X-ray apparatuses ad i 29 portable apparatuses, i differet ceters belogig to the public health etwork, private etwork ad philathropic etwork. Amog the 121 tested apparatuses, ( = 39) preseted problems regardig the collimatio system accuracy ad/or aligmet of the X-ray beam cetral ray, most of those 39 apparatuses ( = 22) belogig to private ceters. Amog the tested apparatuses, ( = 29) were classified as fixed X-ray apparatuses with problems, while 8.26 ( = 10) were portable apparatuses that were ot compliat with the quality assurace stadards. I 2009, 117 apparatuses (89 fixed ad 28 portable) were tested i the Paraíba state. Amog those apparatuses, ( = 23) preseted problems i the collimatio Figure 1. Collimatio system accuracy test. Image demostratig compliat fields cogruece. Figure 2. Collimatio system accuracy test. Image demostratig o compliat fields cogruece. Figure 3. Cetral ray perpedicularity test. Image demostratig the compliat icidece of the X-ray beam cetral ray. Figure 4. Cetral ray perpedicularity test. Image demostratig the o compliat icidece of the X-ray beam cetral ray. 246

4 system accuracy ad/or X-ray beam aligmet, most of them ( = 13) belogig to private cliics. As regards the classificatio of the apparatuses, amog all the apparatuses moitored i 2009, ( = 15) were classified as fixed apparatuses with problems, ad 6.83 ( = 8), as portable, o compliat apparatuses. I the preset study, ( = ) of the apparatuses tested i 2008 were tested agai i 2009, with improvemet i QCT results of 18.6 ( = 16) from oe year to aother (Figures 5 ad 6). The other apparatuses tested i both years obtaied the same satisfactory results o the collimatio system accuracy ad cetral ray perpedicularity tests, with o chage i results. I the collimatio system accuracy tests performed i 2008 ad 2009, results improvemet was observed i ( = 11) of the apparatuses with fields cogruece i coformity with the stadards (Table 1). Improvemet was also observed i X-ray beam cetral ray perpedicularity test, i 5.82 ( = 5) of the apparatuses tested i both years (Table 2). DISCUSSION Table 1 Classificatio of the fixed ad portable X-ray apparatuses, accordig to the collimatio system accuracy tests performed i 2008 ad Fixed ad portable X-ray apparatuses Compliat fields cogruece No compliat fields cogruece Total umber of X-ray apparatuses, umber of X-ray apparatuses Table 2 Classificatio of fixed ad portable X-ray apparatuses, accordig to X-ray beam cetral ray perpedicularity tests performed i 2008 ad Fixed ad portable X-ray apparatuses Compliat cetral ray icidece No compliat cetral ray icidece Total umber of X-ray apparatuses, umber of X-ray apparatuses Figure 5. Chart demostratig the classificatio of the X-ray apparatuses ito fixed ad portable apparatuses, accordig to the results of the quality cotrol tests performed i the Paraíba state i Figure 6. Chart demostratig the classificatio of the X-ray apparatuses ito fixed ad portable apparatuses, accordig to the results of the quality cotrol tests performed i the Paraíba state i I the preset study, it was observed that i all the visits, o istitutio had a QAP i radiodiagosis, cotraveig the Order 453/98 of the Miistry of Health which recommeds the periodical testig i all the diagostic X-ray apparatuses with the purpose of maitaiig such equipmet i appropriate operatioal coditios. The collimatio system accuracy test ad X-ray beam aligmet test recommeded by the Order 453/98 must be performed every six moths ad aually, respectively. I the preset study, the periodicity of both tests was aual, followig the aual routie of health surveillace ispectios at medical X-ray ceters. Additioally, the lack of such a program cotributes to the image quality deterioratio, with the cosequetial icrease i wastig of films ad repetitio of imagig studies, thus icreasig the radiatio exposure for both patiets ad workers (4,5). Curretly, difficulties regardig the awareess of the regulatig agecies o the importace of eforcig the implemetatio of such programs i the istitutios i the Paraíba state are still observed. Additioally, there is a lack of qualified professioals for such programs, ad scarcity of qualified ad experieced techicias for equipmet maiteace oce the problems are detected. Not oly traiig i radioprotectio for all idividuals ivolved i the operatio of radiatio emittig equipmet is ecessary, but it also ecessary to assure a perfect operatio of such equipmet. The collimatio system accuracy tests performed i 2008 demostrated that 22.1 ( = 19) of the evaluated apparatuses were o compliat with the light ad radiatio fields cogruece tests (Table 1), 247

5 with results similar to the oes reported by Medeiros & Alves (12) (17) ad lower tha those observed by Silva et al. (13) (30) ad Carrizales & Cozma (14) (41). As regards the X-ray beam cetral ray aligmet, the results observed i the preset study (11.63; = 10) were very low as compared with the results observed by Carrizales & Cozma (14) (53), i the cases where the radiology ceters did ot follow a QAP. As regards the QCTs performed i 2009, the prevalece of o compliat apparatuses i the light ad radiatio fields cogruece tests correspoded to 9.31 ( = 8) (Table 1), a percetage higher tha the oe reported by Bacelar et al. (15) (5) ad lower tha the oe observed by Gori et al. (16) (13). As regards the X-ray beam cetral ray aligmet, a differece was observed i the umber of o compliat apparatuses i 2009 (5.82; = 5) i compariso with the previous year, a percetage cosiderably lower tha the oe reported by Silva et al. (13) (17,7). CONCLUSIONS By testig the light ad radiatio fields cogruece ad the X-ray beam cetral ray perpedicularity i apparatuses at Paraíba state radiology ceters, it was possible to observe that the o coformities observed were quite sigificat i the first year, demostratig the importace of implemetig quality assurace programs i radiology ceters for prevetio ad maiteace of the X-ray apparatuses. Adjustmets i o compliat apparatuses were oly performed after ispectio ad otificatio o the o compliace by the ispectig agecy (Agevisa-PB), as oe of the radiology ceters i the Paraíba state had a quality assurace program. The QCTs performed i the first year of the preset study (2008) revealed a high idex of o coformities (45.34), that was sigificatly reduced i the followig year (26.74), with ( = 16) of the apparatuses tested i 2008 improvig their performace i The remaiig apparatuses tested i both years obtaied the same satisfactory results. A good X-ray equipmet performace is ot oly a matter of complyig with the regulatios, but also, ad more importatly, a matter of permaet iterest i improvig the quality ad efficiecy at the radiology ceters. Therefore the implemetatio of quality assurace programs at the istitutios operatig diagostic X-ray apparatuses is proposed, with periodical evaluatio ad adjustmet of the equipmet by qualified professioals, with the purpose of producig high quality images to allow correct diagoses, with a reductio of the radiatio dose delivered to patiets ad ivolved professioals exposed to radiatio, as well as reducig the costs for the ceters, as a result of the reductio of imagig studies repetitios. Ackowledgemets The authors wish to thak the team of the Agevisa-PB Techical Board of Directors of Medical Sciece ad Techology ad Correlates for the support i the developmet of the preset study. REFERENCES 1. Furquim TAC, Costa PR. Garatia de qualidade em radiologia diagóstica. 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